Reagents (e.g. acetic acid), process promotors (e.g. softeners), and dyes--all called agents hereinafter--are employed in the textile-finishing industry in specific processing machinery and equipment.
How much of each agent is needed for a specific processing stage is often prescribed in a recipe. The agent for each stage in the finishing of a textile must be portioned or metered out and dispatched to the corresponding machinery or equipment. The various amounts are often dissolved or fine-dispersed in liquids (e.g. water). In this event the liquid can also act as a carrier. Agent is in the simplest case brought to the textile-finishing machinery or equipment by hand, in pails for example, and there added either directly to the machinery or equipment or to a storage container (e.g. the feed tank of a dye vat). Automating the procedure is known. Holding tanks (e.g. feed tanks or solution tanks) installed at a central point, in the kitchen of the dye works for example, can communicate through pipelines with the machinery or equipment. When agents have to be dissolved, in water for example, the containers often have mixers, heaters, and other auxiliary equipment associated with them. The ensemble of such a container and its associated auxiliary equipment will be called a holding point hereinafter, although the term is not to be considered as exclusive. Such a holding point can also have instead of the auxiliary equipment a line that supplies it with agent from a production line through a dosimeter. Large volumes of agent can be kept on hand at such a holding point. Enough for the particular stage can be removed and dispatched to the processing point. It is on the other hand also possible to prepare and hold one or more batches of just enough agent for the particular stage and dispatch it to the processing point as needed.
The processing points in what follows are to be understood as each comprising specific processing machinery and equipment (e.g. dying machines or scouring becks), in which the textile is processed by adding the agent.
One type of facility for automatically dispatching agents to processing points from holding points is comparatively simple and extensively employed. Each machine and piece of equipment is associated with its own holding tank by way of an unbranched pipeline. When there are several machines or pieces of equipment, as at a processing point for example, this approach demands relatively many holding tanks, holding points in other words. The pipeline is expensive, and a lot of space is consumed. Again, since the lines are usually very long, they are inefficient to operate.
Such facilities are accordingly often recirculating or branched to allow the processing points to be alternately connected to and disconnected from the various holding points by valves. Although such a facility does make it possible to get along with less holding tanks and points than an unbranched facility can, it is, with all its pipelines and valves, considerably more complicated and expensive.